Precision miniature sexless coaxial connector



O 1970 H. W.BANNING 3,

PRECISION MINIATURE SEXLESS COAXIAL CONNECTOR Filed Dec. 16, 1968 FlG.2

INVENTOR. HARMON W. BANNING ATTORNEYS United States Patent US. Cl.339-48 6 Claims ABSTRACT OF THE DISCLOSURE A miniature sexless coaxialconnector is characterized by an inner conductor sliding springmechanism to establish coupling between like connectors whileintroducing negligible mismatch.

BACKGROUND OF THE INVENTION The present invention relates to precisionsexless miniature connectors and more particularly concerns a novelminiature coaxial connector suitable for use with 3.5 millimeter lineswhile introducing negligible mismatch or unwanted resonances.

The use of a Spring-l0aded inner conductor for a precision coaxialsexless connector is not in and of itself new. There exists such aconnector for use in 7 mm. coaxial lines. However, practicaldifliculties are encountered when merely scaling down this connector tothe 3.5 mm. size.

Accordingly, it is an important object of this invention to provide aprecision sexless coaxial connector suitable for use with 3.5 mm. linesthat is reliable, relatively easy and inexpensive to fabricate andexhibits excellent electrical properties over a wide bandwidth.

It is a further object of the invention to achieve the preceding objectwhile introducing relatively little mismatch over a wide range offrequencies.

SUMMARY OF THE INVENTION According to the invention, there are meansdefining an outer conductor and an inner conductor assembly having aninside portion maintained in fixed relationship with respect to theother conductor means and an outside portion that is axially slideableand radially fixed relative to the axis of the connector. The innerconductor assembly includes spring means in a region around an outsidestud that is inside the circularly cylindrical cavity at the inside endof the inner conductor outside portion. The bottom of this cavity isdefined by an annular shoulder or base formed with an opening ofdiameter slightly larger than the diameter of the stud, but slightlyless than the diameter of a screwhead. The stud is internally tapped toaccommodate a screw having that screwhead so that the screwhead coactswith the base to limit the outward movement of the outside portion asthe surrounding spring urges the inside and outside portions apart toinsure good contact with the inner conductor of a like sexless coaxialconnector. The inside portion also includes a beveled shoulder uponwhich the inside surface of the outside portion rides.

Numerous other objects, advantages and features of the invention Willbecome apparent from the following specification when read in connectionwith the accompanying drawing in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal sectional viewthrough a connector according to the invention; and

FIG. 2 is a sectional view through the inner conductor assemblyaccording to the invention.

3,533,046 Patented Oct. 6, 1970 DETAILED DESCRIPTION OF PREFERREDEMBODIMENTS With reference now to the drawing and more particularly FIG.1 thereof, there isshown a sectional view through a connector accordingto the invention. The outer conductor assembly includes a mainconducting portion 11 that carries an annular-dielectric bead 12 in theinside end of the connector surrounding an inner conductor inside endportion 13 of slightly smaller diameter than the main length of theinner conductor so that the characteristic impedance of the connectoralong the entire length is substantially constant. The inner conductorassembly includes a fixed inside portion 14 that is supported by threeradial pins 15 equiangularly disposed about the connector axis betweencompensating pairs of holes, such as 16. The outer conductor assemblyalso carries a crenellated alignment ring 17 at its outside end that isheld in place by the internally and externally threaded collar 21. Aninternally threaded coupling nut 22 completes the outer conductorassembly.

The inner conductor assembly includes a moveable outside portion 23 thatis slideable along the axis of the connector but maintained in preciseconcentric relationship with respect to the outer conductor.

Referring to FIG. 2 there is shown a detailed magnified longitudinalsectional view of the inner conductor assembly near the outside end ofthe connector helpful in understanding the invention. The unitarycircularly cylindrically symmetrical conducting part 24 is formed withan outside stud 25 that fits snugly within the hollow end of assembly 14in fixed relationship thereto. Its outside end is formed with a stud 26having a threaded opening 27 for accommodating a screw 31. A hollowconducting cylinder 32, urged away from conducting member 24 by spring30 and limited in axial end travel by the head of screw 31, completesthe inner conductor assembly. A feature of the invention resides informing the shoulder 33 of member 24 upon which the inside wall ofmember 32 slides slightly bevelled as shown to help reduce electricalmismatch. Member 32 is formed with a central opening 34 of diameterslightly greater than that of outside stud 26 and less than the diameterof the head of screw 31 and the diameter of spring 30. Actual contactwith the inner conductor of a like mating connector occurs along theannular outer surface 35 as the spring 30 urges member 32 against a likemember to insure good reliable contact.

Referring again to FIG. 1, actual connection occurs by sliding back thecoupling nut 22 on one connector and screwing the coupling nut of theother connector around the outside threads of member 21 as thecrenelated alignment rings and the two connectors interleave and engageone another. The specific crenelated ring and coupling nut assembly isknown in the art and not a part of this invention.

The invention is relatively easy and inexpensive to fabricate. Themember 24 may be accurately formed. Assembly is relatively easy toaccomplish by putting spring 30 over stud 26, sliding member 32 overmember 24, and screwing screw 31 into threaded opening 27.

There has been described a novel connector assembly that represents apractical high performance 3.5 mm. sexless coaxial connector. It isevident that those skilled in the art may now make numerous uses andmodifications of and departures from the specific embodiment describedherein without departing from the inventive concepts. Consequently, theinvention is to be construed as embracing each and every novel featureand novel combination of features present in or posessed by theapparatus and techniques herein disclosed and limited solely by thespirit and scope of the appended claims.

The bevelling of shoulder 33 performs a dual function. It provides ameans for effecting good contact with the inside wall of hollowconducting cylinder 32 over a range of relative axial displacement. Italso increases slightly the effective diameter of the outer surface ofcylinder 32 (this cylinder having four longitudinal slots in spacequadrature to permit some expansion) to introduce an eifective capacitythat compensates for the inductive effect of the gap immediatelyadjacent to the cylinder open end and of the slots.

The slight difference between the diameter of opening 34 and stud 26allows a slight axial misalignment of inner conductors of matingconnectors to insure a good connection with good electricalcharacteristics despite slight mechanical imperfections.

What is claimed is:

1. A precision miniature coaxial sexless connector comprising:

means defining an outer conducting surface having an inside axis,

an inner conductor assembly inside said means defining an outerconductor,

said inner conductor assembly including an outside stud of firstdiameter contiguous with a shoulder of second diameter" greater thansaid first diameter and formed with an internally threaded opening forre ceiving a screw,

a hollow conducting element open at one end having its inside wallaxially slideable along said shoulder and having a base at the other endformed with an opening of third diameter slightly larger than said firstdiameter,

spring means in the region between said shoulder and said base urgingsaid shoulder and said base apart,

4 v and a screw in said threaded opening having a head of fourthdiameter slightly greater than said'thirddiameter for limiting the axialdisplacement of said base.

2. A precision miniature coaxial sexless connector in accordance withclaim 1 wherein said shoulder is slightly bevelled.

3. A precision miniature coaxial sexless connector in accordance withclaim 1 wherein said spring means is a helical spring surrounding saidoutside stud and of fifth diameter greater than said third diameter andless than said second diameter.

4. A precision miniature coaxial sexless connector in accordance withclaim 2 wherein said spring means is a helical spring surrounding saidoutside stud and of fifth diameter greater than said third diameter andless than said second diameter.

5. A precision miniature coaxial sexless connector in accordance withclaim 1 wherein said outside stud and said shoulder comprise a unitarystructure.

6. A precision miniature coaxial sexless connector in accordance withclaim 5 wherein said unitary structure comprise an inside stud at itsinside end.

References Cited UNITED STATES PATENTS 2,117,029 5/1938 Larsson 1733322,690,542 9/1954 Pearce 33948 RICHARD E. MOORE, Primary Examiner L. I.STAAB, Assistant Examiner US. Cl. X.R.

